Chemistry: Atoms, Elements and Compounds Flashcards Preview

IGCSE Combined Science > Chemistry: Atoms, Elements and Compounds > Flashcards

Flashcards in Chemistry: Atoms, Elements and Compounds Deck (11)
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1
Q

Describe the difference between physical change and chemical change.

A

Chemical involves a change in the chemical structure of a substance but physical is a change in state.

2
Q

Describe the differences between elements, compounds and mixtures.

A

Element is composed of a singular element, compounds are composed of multiple chemically bonded elements, and mixtures are not chemically bonded.

3
Q

Describe the structure of an atom in terms of
electrons and a nucleus containing protons
and neutrons.

A

An atom is made of a nucleus comprised of protons and neutrons, and an equal amount of electrons to protons orbiting the nucleus in shells to give a neutral charge.

4
Q

Describe the build-up of electrons in
‘shells’ and understand the significance
of the noble gas electronic structures
and of valency electrons (the ideas of the
distribution of electrons in s and p orbitals
and in d block elements are not required).

A

Electron configuration: Shells are layers which can only hold a certain amount of electrons in each layer. These are accordingly placed in periods to show how many layers an atom of an element has.
e.g. Carbon. 2, 6

5
Q

State the relative charges and approximate
relative masses of protons, neutrons and
electrons.

A

Protons - positive charge, relative mass of 1.
Neutrons - no charge, relative mass of 1.
Electrons - negative charge, relative mass of negligible.

6
Q
Define atomic (proton) number and mass
(nucleon) number.
A

Atomic number - Amount of protons.
Mass number - Amount of neutrons + protons.
Atomic number = Mass number - protons.

7
Q

Use proton number and the simple structure
of atoms to explain the basis of the Periodic
Table (see section C9), with special
reference to the elements with proton
numbers 1 to 20. (A copy of the Periodic
Table will be provided in Papers 1 and 3.)

A

Period - number of shells.

Group - number of electrons in valence shell.

8
Q

Describe the formation of ions by electron

loss or gain.

A

Particles are not stable without a full valence shell, and so will swap with other atoms to form ions, and become ionically bonded, losing or gaining electrons. Metals tend to lose electrons, and non-metals gain.

9
Q

Describe the formation of ionic bonds

between elements from Groups I and VII.

A

Group 1 element loses an electron, Group 7 element gains the one the Group 1 element donated. Thus they become ionically bonded.

10
Q

Explain the formation of ionic bonds
between metallic and non-metallic
elements.

A

Metals tend to lose electrons to become stable, and these electrons are donated to non-metals, and thus form an ionic bond. Both ions are stable.

11
Q

State that non-metallic elements form nonionic
compounds using a different type of
bonding called covalent bonding involving
shared pairs of electrons.

A

Non-metallic elements can bond by sharing electrons, known as covalent bonding. These bonds are stronger than ionic bonds.